A floor surfacing machine with different drive motors

ABSTRACT

The present disclosure relates to a floor surfacing machine ( 100 ) comprising drive wheels ( 171, 172 ) and a planetary head ( 140 ) with one or more satellite grinding heads ( 120 ), A first drive motor ( 110 ) is arranged to drive the planetary head ( 140 ) and a second drive motor ( 130, 430 ) is arranged to drive the one or more satellite grinding heads ( 120 ). The first drive motor ( 110 ) is arranged to be directly powered only by means of a re-chargeable internal electrical power source ( 310 ) comprised in the floor surfacing machine ( 100 ).

TECHNICAL FIELD

There is disclosed herein a floor surfacing machine comprising a planetary head with one or more satellite grinding heads. A first drive motor is arranged to drive the planetary head and a second drive motor is arranged to drive the one or more satellite grinding heads.

BACKGROUND

A floor surfacing or grinding machine is commonly used to strip or smooth flooring surfaces by grinding away undesired material. Floor surfacing machines provide clean, smooth, and essentially flat surfaces to which new coverings or coatings can be applied. Floor surfacing machines are also commonly used to smooth rough flooring surfaces or to remove surface levelling compounds to create a floor which has a smooth and level surface. Certain surfaces, including some types of concrete, are also suitable for polishing using a floor surfacing machine.

One common type of a floor surfacing machine is the planetary-type machine. This type of machine normally comprises two to four, or even more, satellite grinding heads mounted to a larger planetary head, where the satellite grinding heads may be driven in one direction and the planetary head in another direction. A motor, normally an electrical motor, drives both the satellite grinding heads and the planetary head, where transmission is accomplished by means of transmission belts and belt pulleys. The motor is either a combustion engine or powered from the electrical mains of a power network.

Some floor grinding machines comprise a first motor arranged to drive the planetary head, and a second motor arranged to drive the satellite grinding heads. U.S. Pat. No. 6,540,596 B1 discloses a surfacing machine with two drive motors.

A floor surfacing machine normally requires high power to operate. When powered by cable from electrical mains, a 32 Ampere (A) source or higher may be required. However, many construction sites only provide 16 A sources, which is not enough for powering floor surfacing machines requiring more power. Thus, starting to use a floor surfacing machine can be delayed, made more difficult, or in the worst case made impossible, in those cases in which the electricity distribution grid at the location cannot supply the current that the floor surfacing machine requires.

It may not even be possible for the floor surfacing machine to be driven off of the transport vehicle with which it has been transported to the relevant work location, due to the lack of a required external power source such as electrical mains available. It is of course possible to have a portable power supply system, but such a solution is naturally expensive and cumbersome to handle.

There is thus a need for floor surfacing machines which are able to operate also at such construction/work sites. cl SUMMARY

It is an object of the present disclosure to provide a floor surfacing machine that is able to operate at construction/work sites where sufficient electrical power is unavailable.

This object is accomplished by means of a floor surfacing machine that comprises drive wheels and a planetary head with one or more satellite grinding heads, where a first drive motor is arranged to drive the planetary head and where a second drive motor is arranged to drive the one or more satellite grinding heads. The first drive motor is arranged to be directly powered only by means of a re-chargeable onboard electrical power source comprised in the floor surfacing machine.

This means that the first drive motor that is arranged to drive the planetary head can be powered separately, such that the electrical power available can be used to power the second drive motor that is arranged to drive said satellite grinding heads.

According to some aspects, the internal onboard power source is adapted to be charged by a battery charger that in turn is adapted to be powered by an external electrical power source.

In this manner, the onboard electrical power source can be easily recharged when necessary.

According to some aspects, the floor surfacing machine comprises an onboard battery charger that is adapted to charge the onboard electrical power source.

This means that a battery charger always is available.

According to some aspects, the second drive motor is an internal combustion engine.

This means that the floor surfacing machine can be used where there is no external power source such as electrical mains available.

According to some aspects, the internal combustion engine is fueled by propane.

This provides an environment-friendly internal combustion engine.

According to some aspects, the second drive motor comprises an electrical generator that is adapted to power a battery charger that is adapted to charge the onboard electrical power source.

This means that the onboard electrical power source can be charged without access to an external power source such as electrical mains.

According to some aspects, the floor surfacing machine comprises an internally arranged battery charger that is adapted to charge the onboard electrical power source and is connected to the electrical generator.

This means that a battery charger always is available.

According to some aspects, the second drive motor is arranged to be directly powered by an electrical mains connection.

According to some aspects, the second drive motor is arranged to be directly powered only by means of the re-chargeable onboard electrical power source.

This means that both drive motors have a stable power supply and, in addition to this, also can be operated without connection to the electrical mains as long as the chargeable onboard electrical power source is sufficiently charged.

According to some aspects, the onboard electrical power source is adapted to provide a battery current that is divided into a first current to the first drive motor and a second current to the second drive motor. In a certain operational state, the first drive motor is adapted to act as a generator and generate a third current that adds to the second current.

This means that energy that is created by means of the operation of the floor surfacing machine is re-used, increasing the running time between having to charge the onboard electrical power source.

According to some aspects, the floor surfacing machine comprises a drive arrangement configured to propel the drive wheels. The drive arrangement comprises at least one electric motor that is adapted to be powered by means of a re-chargeable onboard electrical power source.

This means that the floor surfacing machine easily can be driven off of the transport vehicle with which it has been transported to the relevant work location, even without access to an external power source such as electrical mains.

According to some aspects, the same onboard electrical power source is adapted to power the first drive motor and the drive arrangement.

This means that only one onboard electrical power source is needed.

According to some aspects, a separate onboard electrical power source is adapted to only power the drive arrangement.

This means that the drive arrangement can be powered by means of an onboard electrical power source that is adapted for the requirements of the drive arrangement.

According to some aspects, the drive arrangement comprises a sensing arrangement that is adapted to switch between having the drive arrangement powered by the onboard electrical power source or by the electrical mains dependent on the power presently available from the onboard electrical power source and the electrical mains.

In this way, the onboard electrical power source is used for powering the drive arrangement only when electrical mains is not available.

According to some aspects, the onboard electrical power source is positioned above the wheels such that the weight of the onboard electrical power source provides a pressure of the wheels towards a floor. The pressure is adapted to increase traction of the floor surfacing machine.

According to some aspects, the onboard electrical power source is positioned such that, during operation of the floor surfacing machine, an extension along a closest distance between a mass center of the onboard electrical power source and the floor passes between the drive wheels.

This provides a pressure of the wheels towards a floor, where the pressure is adapted to increase traction of the floor surfacing machine.

According to some aspects, the re-chargeable onboard electrical power source is constituted by a battery.

According to some aspects, the internal onboard power source is adapted to be charged by a battery charger that in turn is adapted to be powered by an external electrical power source that is constituted by a 12 VDC or 24 VDC supply.

Such an external electrical power source can be available in a transport vehicle which means that the battery charger can be charged during transport to and from work sites.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to “a/an/the element, apparatus, component, means, step, etc.” are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following description. The skilled person realizes that different features of the present invention may be combined to create embodiments other than those described in the following, without departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will now be described more in detail with reference to the appended drawings, where:

FIGS. 1A-D illustrate views of an example floor surfacing machine.

FIGS. 2A-B show an example planetary head with satellite grinding heads;

FIG. 3 schematically illustrates how the drive motors are powered according to a first example;

FIG. 4A schematically illustrates how the drive motors are powered according to a second example;

FIG. 4B schematically illustrates a further aspect of the second example;

FIG. 5A-B schematically illustrate a lower part of the floor surfacing machine;

FIG. 6A-B schematically illustrate examples of drive arrangements

FIG. 7 schematically illustrates how the drive motors are powered according to a third example;

FIG. 8 schematically illustrates rotation directions of the planetary head and the satellite grinding heads; and

FIG. 9 schematically illustrates an example of a first drive motor.

DETAILED DESCRIPTION

The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain aspects of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments and aspects set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout the description.

FIGS. 1A-1D illustrate views of a floor surfacing machine 100, such as a floor grinding machine, comprising two drive motors 110, 130. A first drive motor 110 is arranged to drive a planetary head 140. A second drive motor 130 is arranged to drive a plurality of satellite grinding heads 120. A cover 107 protects the planetary head 140 and the satellite grinding heads 120 and allows for dust and debris to be sucked up via an outlet opening 160.

A forward direction F of the floor surfacing machine 100 is defined as extending away from the handle part 105 which comprises the user controls 109 for operating the machine. The forward direction F can also be said to be extending away from wheels 171, 172 of the floor surfacing machine 100. A lateral direction extends orthogonal to the forward direction, i.e., orthogonal to an extension plane P of the wheels 171, 172, shown in FIG. 1B.

The left 171 and right 172 wheels of the floor surfacing machine 100 are attached via respective wheel support assemblies 106. According to some aspects, the floor surfacing machine 100 also comprises a support wheel 173 arranged in front of the wheels 171, 172 and being intended to be used during transport of the floor surfacing machine 100. According to some aspects, each wheel support assembly 106 also comprises an integrated drive arrangement 190 configured to propel the wheels 171, 172 which then are constituted by drive wheels 171, 172. The drive arrangement 190 may, e.g., be based on electric motors connected to respective drive wheels 171, 172, or a common electric motor that is adapted to propel the drive wheels 171, 172. According to some further aspects, alternatively, there is no integrated drive arrangement 190 configured to propel any drive wheels, only wheels 171, 172 that are adapted for manual maneuvering of the floor surfacing machine 100.

The drive arrangement 190 may be arranged in any other suitable manner, and there may be only one drive arrangement 190 adapted to propel both wheels 171, 172. Generally, according to some aspects, the floor surfacing machine 100 comprises drive wheels 171, 172 and a drive arrangement 190 configured to propel the drive wheels 171, 172, where the drive arrangement 190 according to some aspects comprises at least one electric motor, and preferably two electric motors one for driving the left drive wheel 171 and the other for driving the right drive wheel 172.

The floor surfacing machine 100 may be operated by controls on the machine, and/or remotely via remote control.

FIGS. 2A and 2B illustrate details of the drive arrangement for driving the satellite grinding heads 120. Each satellite grinding head 120 is fixedly attached to a belt pulley 210, which is driven by a belt 220 from a central pulley 260 driven by a motor axle 135 of the second drive motor 130. The floor surfacing machine 100 normally comprises three satellite grinding heads 120, but any suitable number of grinding heads can be provided, typically two—five satellite grinding heads.

The planetary head 140 is rotated about the motor axle 135 of the second drive motor 130 by the first drive motor 110. The direction of rotation R1 of the planetary head 140 and the direction of rotation R2 of the satellite grinding heads are controlled independently from each other, which is an advantage.

Floor surfacing machines such as the floor surfacing machine 100 with independently operable first and second drive motors were described in U.S. Pat. No. 6,540,596 B1, and also in SE 539 542 C2, and will therefore not be discussed in more detail herein.

With reference to FIG. 3 , schematically illustrating a first example according to the present disclosure, the first drive motor 110 is connected to an internal power source such as a battery 310 that can be an onboard battery, which battery 310 according to some aspects is connectable to an external, or internally arranged, battery charger 330. According to some aspects, an internally arranged battery charger is an onboard charger that under normal operating conditions is adapted to travel with the floor surfacing machine 100 together with an onboard battery 310. In this context, a battery charger is a conventional battery charger of any suitable type that provides a certain voltage and charging current for the battery 310. The battery charger can be provided by well-known protection circuitry that for example avoid over-charging and over-heating, as well as internal leakage and short-circuit.

According to some further aspects, the second drive motor 130 is adapted to be connected to an external power supply such as electrical mains 320 of a power network. This means that when the floor surfacing machine 100 is in operation, only the second drive motor 130 is using power from the electrical mains 320, and only the power requirement of the second drive motor 130 limits where the floor surfacing machine 100 can be operated. By adapting the second drive motor 130 to require no more than 16 Amperes, the floor surfacing machine 100 can be operated at most work sites without problem. The remainder of the floor surfacing machine's power requirement may be provided by means of the battery 310.

According to some aspects, in the case of an internally arranged battery charger 330, the battery charger 330 can be activated when the second drive motor 130 is connected to the electrical mains 320, either automatically or by means of a setting inferred by a user.

If admitted by the available power supply of the electrical mains 320 and the present power consumption of the first drive motor 110, the battery 310 can be charged during operation of the floor surfacing machine 100. Otherwise, the battery charger 330 is only activated when the floor surfacing machine 100 is not running or partially running, for example if only the first drive motor 110 is not running.

According to some aspects, with reference to FIG. 4A that schematically illustrates a second example, the second drive motor 430 is a combustion engine, for example a propane engine. This means that electrical mains 320 only are needed when the battery 310 is to be charged. Alternatively, or as a supplement, as indicated with dashed lines, the second drive motor 430 comprises a generator 440 that is connectable to the battery charger 330 for charging the battery 310 when the second drive motor 430 is running. In this case, according to some further aspects, the generator 440 can be disengaged if all available power generated by the second drive motor 430 has to be used for a grinding procedure. The battery charger 330 can be either external or internally arranged, examples of this will be discussed more in detail below.

The combustion engine can utilize any mixture of propane and butane. Such mixture is often called Autogas or liquefied petroleum gas (LPG). Compared to gasoline or diesel engines, propane engines generate very little harmful emissions, and can therefore be used indoors.

A propane fueled combustion engine can be designed to provide high power at reasonable weight, which is an advantage. The propane engine is also relatively easy to start, even in cold weather, since the fuel is already is gaseous form. In addition, propane engines burn cleaner than gasoline engines, which leads to lower maintenance, such as less frequent oil changes, and to longer lasting engine parts.

FIG. 4B corresponds to FIG. 4A and schematically illustrates further aspects of the present disclosure, where both an internal battery charger 33A and an external battery charger 330B are indicated with dashed lines as being possible optional and/or alternatives, even in combination. Regarding having an internal battery charger and/or an external battery charger, it is conceivable that the battery 310 can be charged by an internal battery charger 330A that is comprised in the floor surfacing machine 100, as well as by an external battery charger 330B. An internal battery charger 330A can according to some aspects be inaccessible within the floor surfacing machine 100 and only be used for charging by means of the generator 440, and an external battery charger 330B can be used for charging via the electrical mains 320. Alternatively or as a complement, the different battery chargers 330A, 330B can have different charging efficiency depending on the intended available input power.

Several types of external battery chargers can be available for an operator depending on the available charging power. For example, a three-phase battery charger can normally provide a more efficient charging than a one-phase battery charger.

The battery 310 can thus be adapted to be charged by an internal battery charger 330A only, and an external battery charger 330B only, or by both an internal battery charger 330A and an external battery charger 330B. In the case of the battery 310 being adapted to be charged by an internal battery charger 330A only, the internal battery charger 330A should suitably be adapted to be connectable to the electrical mains 320. In this context, when an internal battery charger 330A is mentioned to be inaccessible within the floor surfacing machine 100, this does according to some aspects mean that the internal battery charger 330A at least does not have any connections that are accessible or available for an operator.

According to some aspects, as a possibility that is applicable for all examples, when the drive arrangement 190 is constituted by electric wheel motors connected to the respective drive wheel 171, 172, the electric wheel motors 190 are powered by the battery 310. Alternatively, an operator can choose whether the electric wheel motors 190 are powered by the battery 310 or by the electrical mains 320. According to some aspects, the drive arrangement 190 comprises a sensing arrangement 502 that is adapted to switch between having the electric wheel motors 190 powered by the battery 310 or by the electrical mains 320 dependent on the power presently available from the battery 310 and the electrical mains 320 in view of present operating and charging conditions. Having the opportunity to have the electric wheel motors 190 powered by the battery 310 enables an operator to easily move and load/unload the floor surfacing machine 100 even if an electrical mains supply is unavailable or hard to reach. Loading/unloading of a floor surfacing machine 100 may involve transporting the floor surfacing machine 100 upwards or downwards a loading ramp or similar, where operating wheel motors are desirable. According to some aspects, the wheels 171, 172 can be driven by a single common wheel motor that can be powered as described above. The above is of course also applicable for the case of a common electric wheel motor connected to the drive wheels 171, 172.

Furthermore, as schematically indicated in FIG. 1A, FIG. 1C, FIG. 5A and FIG. 5B and according to some further aspects, the battery 310 is positioned above the wheels 171, 172, overlapping the wheels 171, 172 seen from above, such that the weight of the battery 310 provides an enhanced pressure of the wheels 171, 172 towards the floor 500. Preferably, the battery 310 is mounted on the machine in a position so as to overlap the common axis of rotation of the two drive wheels 171, 172 along a direction being perpendicular to a plane defined by the lowest portions of the driving wheels 171, 172 and the satellite grinding heads 120.

By using the weight of the battery 310, the drive wheels 171, 172 of the floor surfacing machine 100 are weighted down to provide traction, where the weight comprised in the battery 310 is well positioned to provide traction.

According to some aspects, with particular reference to FIG. 5A and FIG. 5B, the battery 310 is positioned such that, during operation of the floor surfacing machine 100, an extension along a closest distance D between a mass center 501 of the battery 310 and the floor 500 passes between the wheels 171, 172.

According to some aspects, the battery 310 is positioned such that, during operation of the floor surfacing machine 100, an extension along a closest distance D between a part of the battery 310 and the floor 500 passes between the wheels 171, 172.

According to some aspects, as an example the first motor 110 is rated 1.5 kW, and the battery 310 is rated 9 kWh, which means that a fully charged battery lasts for about six hours that normally is fully satisfactory.

In the case of the second motor being a combustion engine 430 with a generator 440 that is adapted to charge the battery 310 via a battery charger during operation, the battery will last even longer.

The present disclosure is not limited to the examples above but may vary freely within the scope of the appended claims. For example, the user controls 109 can comprise a battery charge indicator, where the battery's remaining power is indicated, as well as the progress of a running charging procedure. According to some aspects, the user controls 109 comprise a battery condition indicator that is adapted to indicate different battery conditions such as for example overheated, unable to charge, low capacity, internally damaged etc. Such a battery condition indicator can be integrated with the battery charge indicator.

According to some aspects, the user controls 109 comprise control means for controlling charging the battery 310 or not in the case of the floor surfacing machine 100 comprising a generator 440 that is adapted to power a battery charger 330, 330A. It is conceivable that the second drive motor 430 is used for running the generator 440 even when the floor surfacing machine 100 is stationary in order to charge the battery 310. The battery 310 the floor surfacing machine 100 comprising a generator 440 can of course also be charged by a battery charger 330, 330A, 330B powered by the electrical mains 320 when the floor surfacing machine 100 is stationary.

Other types of internal power sources than a battery is conceivable, for example a fuel cell. Generally, the first motor 110 is adapted to be directly powered only by means of a re-chargeable onboard electrical power source 310 comprised in the floor surfacing machine, where, according to some aspects, the re-chargeable electrical power source 310 is internally arranged in the floor surfacing machine 100, being onboard the floor surfacing machine 100, and suitably integrated with the floor surfacing machine 100. In the case of a fuel cell or similar, the charging is accomplished by providing a suitable fuel.

In the case of a battery being used, the battery is to be regarded as a battery arrangement that can comprise one or more separate batteries, where each battery can comprise any number of battery cells or the like, and being of any suitable type such as Li-ion.

According to some aspects, the battery 310 is easily removable for an operator, either in the case of malfunction, or when an operator has one or more spare batteries for the case of a present battery being depleted of power before the operator intends to finish working for the day.

A general concept of the present disclosure is that the first drive motor 110 that is arranged to drive the planetary head 140 is arranged to be directly powered only by means of a re-chargeable internal electrical power source 310 comprised in, and being positioned onboard the floor surfacing machine 100, suitably integrated with the floor surfacing machine 100, while the second drive motor 130, 430 that is arranged to drive the one or more satellite grinding heads 120 is arranged to be powered by means of another power source such as the electrical mains or being in the form of a combustion engine that here has been exemplified by a propane fueled combustion engine.

According to some aspects, a petrol fueled combustion engine is conceivable as well. for the second drive motor 430.

According to some aspects, as illustrated with a dashed connection line 340 in FIG. 3 , the battery 310 can be used as an auxiliary power source for the second drive motor 130. This can be advantageous in cases of an inadequate or malfunctioning external electrical network 320 that, at least during sometimes, is not able to provide sufficient power to the second drive motor 130. Another example where the battery 310 is used for powering both drive motors 110, 130 will be discussed later with reference to FIG. 7 .

According to some aspects, instead of the belt drive arrangement for driving the satellite grinding heads that is illustrated in FIGS. 2A and 2B, a geared transmission can be used.

Regarding the planetary head, FIG. 6A shows an example drive arrangement 600 for driving the planetary head 140 of the floor surfacing machine 100. The drive arrangement 600 comprises a first drive wheel 610 arranged to be driven by the first drive motor 110. A second drive wheel 630 is fixedly attached to the planetary head 140 and arranged to be driven by the first drive wheel 610 via a connecting member 620, such as a chain or a belt. In case a drive chain is used, the first drive wheel 310 and the second 330 drive wheel are sprockets configured to engage the drive chain to bring the planetary head 140 into rotation.

According to some aspects, the drive chain is a self-lubricating chain. This further reduces the maintenance need of the drive arrangement since the self-lubricating drive chain can be designed to last the entire excepted lifetime of the floor surfacing machine 100.

In case a normal chain is used, a protective casing 640 can be designed to hold an amount of lubricating agent, e.g., lubricating oil.

In case a drive belt is used, the first 310 and second 330 drive wheels are belt pulleys configured to engage the drive belt to bring the planetary head 140 into rotation.

FIG. 6B shows a schematic top view of another drive arrangement 600′. Here the connecting member is a geared connection, i.e., a gear train comprising one or more gears 650, 660. The geared connection may be part of a gear transmission arrangement. The geared connecting member also provides a power ratio. In other words, according to some aspects, the connecting member 620 comprises a gear train 650, 660 arranged to transfer power from the first motor 110 to the second drive wheel 630. The gear train may be part of a gear transmission system, i.e., can be configured with a given gear ratio. In case the protective casing 640 is arranged to hold an amount of lubricating agent, e.g., lubricating oil, the geared connection may be lubricated by the agent, thus providing extended service interval, since the lubricating agent is protected from outside contamination.

The internally arranged battery charger 330A is generally constituted by an onboard battery charger 330A that can be easily accessible or more or less integrated in the floor surfacing machine 100.

FIG. 7 shows a third example of the present disclosure. Here, there is a battery charger 730 that is connected to the electrical mains 720. The battery charger 730 is in turn connected to a first battery 710A and is adapted to charge the first battery 710A. According to some aspects, the battery charger 730 comprises a selection device that automatically or manually is adapted to select a power input source, such as for example 400V three-phase AC or 240V one-phase AC.

The first battery 710A is adapted to power both the first drive motor 110 and the second drive motor 130, such that the drive motors 110, 130 are directly powered only by means of the first battery 710A which in turn is charged by the battery charger 730. This means that both drive motors 110, 130 have a stable power supply and, in addition to this, also can be operated without connection to the electrical mains 720 as long as the first battery 710 is sufficiently charged.

During running in a first operational state, the battery 710A provides a battery current i that is divided into a first current i₁ to the first drive motor 110 and a second current i₂ to the second drive motor 130. However, according to some aspects, the operational state can in some running conditions be changed to a second operational state. As shown in FIG. 8 , the planetary head 140 has a planetary direction of rotation R, and the satellite grinding heads 120 have a respective satellite direction of rotation r₁, r₂, r₃ which are opposite the planetary direction of rotation R. During the second operational state, when the second drive motor 130 runs the satellite grinding heads 120, the rotation power induced, and the friction of the grinded floor, causes the planetary head 140 to rotate in the planetary direction of rotation R. This means that instead of drawing the first current ii, the first drive motor 110 acts as a generator and generates a third current i3 that adds to the second current i2 as Illustrated in FIG. 7 .

With reference to FIG. 1C, FIG. 1D, FIG. 5A, FIG. 5D and FIG. 7 , according to some aspects the floor surfacing machine 100 of the third example comprises drive wheels 171, 172 and a drive arrangement 190 configured to propel the drive wheels 171, 172, where the drive arrangement 190 comprises at least one electric motor. In the following, two alternatives are presented.

The first alternative is indicated with dash-dotted lines in FIG. 7 . Here, a separate second battery 710B is adapted to power the drive arrangement 190 in order to enable the drive arrangement 190 to propel the drive wheels 171, 172. The second battery 710B is adapted to be charged by the same battery charger 730 as the first battery 710A, but an alternative charger is of course conceivable.

The second alternative is indicated with dashed lines in FIG. 7 . Here, the first battery 710A is adapted to power the drive arrangement 190 in order to enable the drive arrangement 190 to propel the rive wheels 171, 172. The same battery 710A is thus adapted for powering the first drive motor 110, the second drive motor 130 and the drive arrangement 190.

A combination between the first example and the second example is of course conceivable.

According to some aspects, the battery charger 730 is either an external battery charger, or an onboard battery charger. The battery charger 730 can also in practice comprise two or more separate battery sub-chargers, where one or more battery sub-chargers are external and one or more battery sub-chargers are positioned onboard.

FIG. 9 shows an example of the first drive motor 110 that comprises a DC/AC converter 901 that is adapted to convert a DC battery supply 903 to AC that is used in an electric motor 902 that according to some aspects can be a synchronous motor or a permanent magnet motor. In the case of the second drive motor 130 also being battery-driven as for example described above with reference to FIG. 7 , the arrangement of FIG. 9 is applicable for the second drive motor 130 as well.

The electric motor 902 is according to some aspects a three-phase electric motor as indicated in FIG. 9 , which means that the present disclosure enables running a three-phase electric motor 902 from a one-phase electrical mains 720.

According to some aspects, for all examples and illustrated for the third example in FIG. 7 , the battery charger 730 is adapted to be connected to a low-voltage power source, such as a 12 VDC or 24 VDC supply 750 that can be available in a transport vehicle. This means that the battery charger 730 can be charged during transport to and from work sites. Generally, the electrical mains 320, 720 and the 12 VDC or 24 VDC supply 750 all constitute an external electrical power source. The electrical mains 320, 720 is connected to an external power network, and the 12 VDC or 24 VDC supply 750 can either be supplied by an electrical main or by means of a vehicle battery/generator.

In all cases, the first drive motor 110 is arranged to be directly powered only by means of a re-chargeable onboard electrical power source 310 comprised in the floor surfacing machine 100. For the examples according to the third example illustrated in FIG. 7 , the first drive motor 110 can be indirectly powered by the electrical mains 720 or the 12/24 VDC supply 750. Any of these is adapted to power the battery charger 730, where the battery charger 730 is adapted to charge the battery 710A. The battery 710A, that generally is constituted by a re-chargeable onboard electrical power source, is in turn arranged to directly power the first drive motor 110.

An internally arranged battery charger can according to some aspects be regarded as an onboard battery charger.

Generally, the present disclosure relates to a floor surfacing machine 100, 400, 700 comprising drive wheels 171, 172 and a planetary head 140 with one or more satellite grinding heads 120, where a first drive motor 110 is arranged to drive the planetary head 140 and where a second drive motor 130, 430 is arranged to drive the one or more satellite grinding heads 120, wherein the first drive motor 110 is arranged to be directly powered only by means of a re-chargeable onboard electrical power source 310, 710A comprised in the floor surfacing machine 100, 400, 700.

According to some aspects, the internal onboard power source 310, 710A is adapted to be charged by a battery charger 330; 330A, 330B, 730 that in turn is adapted to be powered by an external electrical power source 320, 720, 750.

According to some aspects, the floor surfacing machine 100, 400, 700 comprises an onboard battery charger 330A, 730 that is adapted to charge the onboard electrical power source 310, 710A.

According to some aspects, the second drive motor 430 is an internal combustion engine.

According to some aspects, the internal combustion engine is fueled by propane.

According to some aspects, the second drive motor 430 comprises an electrical generator 440 that is adapted to power a battery charger 330, 330A that is adapted to charge the onboard electrical power source 310.

According to some aspects, the floor surfacing machine 400 comprises an internally arranged battery charger 330A that is adapted to charge the onboard electrical power source 310 and is connected to the electrical generator 440.

According to some aspects, the second drive motor 130 is arranged to be directly powered by an electrical mains connection 320.

According to some aspects, the second drive motor 130 is arranged to be directly powered only by means of the re-chargeable onboard electrical power source 710A.

According to some aspects, the onboard electrical power source 710A is adapted to provide a battery current i that is divided into a first current i₁ to the first drive motor 110 and a second current i₂ to the second drive motor 130 where, in a certain operational state, the first drive motor 110 is adapted to act as a generator and generate a third current i₃ that adds to the second current i₂.

According to some aspects, the floor surfacing machine 100 comprises a drive arrangement 190 configured to propel the drive wheels 171, 172, where the drive arrangement 190 comprises at least one electric motor that is adapted to be powered by means of a re-chargeable onboard electrical power source 310, 710A; 710B.

According to some aspects, the same onboard electrical power source 310, 710A is adapted to power the first drive motor 110 and the drive arrangement 190.

According to some aspects, a separate onboard electrical power source 710B is adapted to only power the drive arrangement 190.

According to some aspects, the drive arrangement 190 comprises a sensing arrangement 502 that is adapted to switch between having the drive arrangement 190 powered by the onboard electrical power source 310, 710A, 710B or by the electrical mains 320, 720 dependent on the power presently available from the onboard electrical power source 310, 710A, 710B and the electrical mains 320, 720.

According to some aspects, the onboard electrical power source 310 is positioned above the wheels 171, 172 such that the weight of the onboard electrical power source 310 provides a pressure of the wheels 171, 172 towards a floor 500, where said pressure is adapted to increase traction of the floor surfacing machine 100.

According to some aspects, the onboard electrical power source 310 is positioned such that, during operation of the floor surfacing machine 100, an extension along a closest distance D between a mass center 501 of the onboard electrical power source 310 and the floor 500 passes between the drive wheels 171, 172.

According to some aspects, the re-chargeable onboard electrical power source 310 is constituted by a battery 310.

According to some aspects, the internal onboard power source 710A is adapted to be charged by a battery charger 730 that in turn is adapted to be powered by an external electrical power source 750 that is constituted by a 12 VDC or 24 VDC supply 750. 

1. A floor surfacing machine comprising drive wheels and a planetary head with one or more satellite grinding heads, wherein a first drive motor is arranged to drive the planetary head and wherein a second drive motor is arranged to drive the one or more satellite grinding heads, wherein the first drive motor is arranged to be powered by means of a re-chargeable onboard electrical power source comprised in the floor surfacing machine, wherein the second drive motors is arranged to be powered by an electrical mains connections.
 2. The floor surfacing machine according to claim 1, wherein the onboard electrical power source is adapted to be charged by a battery charger that in turn is adapted to be powered by an external electrical power source.
 3. The floor surfacing machine according to claim 1, wherein the floor surfacing machine comprises an onboard battery charger that is adapted to charge the onboard electrical power source.
 4. The floor surfacing machine according to claim 1, wherein the floor surfacing machine comprises a drive arrangement configured to propel the wheels, wherein the drive arrangement comprises at least one electric motor that is adapted to be powered by means of a re-chargeable onboard electrical power source.
 5. The floor surfacing machine according to claim 4, wherein the same onboard electrical power source is adapted to power the first drive motor and the drive arrangement.
 6. (canceled)
 7. The floor surfacing machine according to claim 4, wherein the drive arrangement comprises a sensing arrangement that is adapted to switch between having the drive arrangement powered by the onboard electrical power source or by the electrical mains dependent on the power presently available from the onboard electrical power source and the electrical mains.
 8. The floor surfacing machine according to claim 1, wherein the onboard electrical power source is positioned above the wheels such that a weight of the onboard electrical power source provides a pressure of the wheels towards a floor, wherein said pressure is adapted to increase traction of the floor surfacing machine.
 9. The floor surfacing machine according to claim 8, wherein the onboard electrical power source is positioned such that, during operation of the floor surfacing machine, an extension along a closest distance between a mass center of the onboard electrical power source nd the floor passes between the wheels.
 10. (canceled)
 11. The floor surfacing machine according to claim 1, wherein the internal onboard power source is adapted to be charged by a battery charger that in turn is adapted to be powered by an external electrical power source that is constituted by a 12 VDC or 24 VDC supply.
 12. A floor surfacing machine comprising drive wheels and a planetary head with one or more satellite grinding heads, wherein a first drive motor is arranged to drive the planetary head and wherein a second drive motor is arranged to drive the one or more satellite grinding heads, wherein the first drive motor is arranged to be powered by means of a re-chargeable onboard electrical power source comprised in the floor surfacing machine, wherein the second drive motor is an internal combustion engine.
 13. The floor surfacing machine according to claim 12, wherein the internal combustion engine is fueled by propane or butane.
 14. The floor surfacing machine according to claim 12, wherein the onboard electrical power source is adapted to be charged by a battery charger that in turn is adapted to be powered by an external electrical power source.
 15. The floor surfacing machine according to claim 12, wherein the floor surfacing machine comprises an onboard battery charger that is adapted to charge the onboard electrical power source.
 16. The floor surfacing machine according to claim 12, wherein the second drive motor comprises an electrical generator that is adapted to power a battery charger that is adapted to charge the onboard electrical power source.
 17. The floor surfacing machine according to claim 16, wherein the floor surfacing machine comprises an internally arranged battery charger that is adapted to charge the onboard electrical power source and is connected to the electrical generator.
 18. The floor surfacing machine according to claim 12, wherein the floor surfacing machine comprises a drive arrangement configured to propel the wheels, wherein the drive arrangement comprises at least one electric motor that is adapted to be powered by means of a re-chargeable onboard electrical power source.
 19. The floor surfacing machine according to claim 18, wherein the same onboard electrical power source is adapted to power the first drive motor and the drive arrangement.
 20. (canceled)
 21. The floor surfacing machine according to claim 12, wherein the onboard electrical power source is positioned above the wheels such that the weight of the onboard electrical power source provides a pressure of the wheels towards a floor, wherein said pressure is adapted to increase traction of the floor surfacing machine.
 22. The floor surfacing machine according to claim 21, wherein the onboard electrical power source is positioned such that, during operation of the floor surfacing machine, an extension along a closest distance between a mass center of the onboard electrical power source and the floor passes between the wheels,
 23. (canceled)
 24. The floor surfacing machine according to claim 12, wherein the internal onboard power source is adapted to be charged by a battery charger that in turn is adapted to be powered by an external electrical power sourced that is constituted by a 12 VDC or 24 VDC supply. 